Calculates the root mean square of the model by taking the square root of mean of the sum of squares between the truth, \(y\), and the predicted, \(\hat{y}\) at each observation \(i\).
Calculates the root mean square of the model by taking the square root of mean of the sum of squares between the truth, \(y\), and the predicted, \(\hat{y}\) at each observation \(i\).